Alternate projection collating device



Feb. 1, 1949. c. HlNMAN 2,460,350

ALTERNATE PROJECTION COLLATING DEVICE Filed July 12, 1946 2 Sheets-Sheet l Hl 2 5 719 I f 2 i 1 i W l TNESSES I N V EN TOR:

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g. HINMAN ALTERNATE PROJECTION COLLATING DEVICE 2 Sheets-Sheet 2 Filed July 12, 1946 INVENTOR: lmrifm/finmazz,

v ATTORNEYS.

WITNESSES W%6A4 Patented Feb. 1, 1949 UNIED ALTERNATE PROJECTION cormrmc DEVICE chanioirnmman, Washington, D. 0.

Application July-'12, 1946, Serial No. 683,068

4 Claims. 1,

This invention facilitates the collation, that is to say the detailed comparison, of various kinds of graphic representations, with the object of rapidly detecting difierences (or of establishing exact agreement) between two printed pages, or two photographs or maps or engravings :or blueprints or other such objects, which carry matter known to be more'or less'identical. Myinvention is particularly adapted, and I haveused it successfully, for the purpose of collating, pageby page, different copies of the same printed book in, order to determine whether ornot, through either accidental or deliberate changes made in the types while the various copiesofthe edition were being printed, or through any "other causes, corresponding pages of these different copies of the same edition now show difierences. Such differences frequently appear in type-printed books in which the sheets were printed ofi by hand,- as in all books printed before abo'ut1800.

ferences result; sometimes with and sometimes without the intention to deceive), in order to enhancethe value of this damaged or otherwise imperfect copy. Modern scholarship demands accurate knowledge of all such changes fromthe original setting, and these changes can be discovered only by collation. The objectives of collation of this kind are: (1) to learn as much as possible about the physical conditions which affect the transmission of literary documents,

whether being printed for the first time-or being reprinted, with or without editorial or other alterations; and (2) to ascertain as far as possible the text that most nearly represents what the author originally wrote.

Usually collation such as this is done by plac ing two printed volumes alongside each other so that thecollatormay visually comparethem, linebyline and letterby letter, ancl-noteanydifien ences between themgbut this is a very slow and tedious process. My invention is, I believe, the

Moreover, in very rarehooks; i

first mechanism whereby this process is facilitated. To this end I proje-ct the image of a page of one volume and that of the corresponding page in'another volume upon a screen with exact superimposition. This in itself afiords the collator a visual image showing where a letter, say, is distorted by having another letter superimposed on it if the two letters differ. But the detection of these differences is rendered more accurate and verygmuch. more rapid by the use of an occulting device by which the path of the projection ofieach image is'broken. by one of two sectored ceculting discs so geared together that, when the occulting mechanism is set in motion, the two. images are projected to the screen alternately rather than simultaneously. The result is that where the two images are alike the screen shows only a perfectly motionless picture, but that where the two images differ a very noticeable flicker occurs, by this word flicker I denote a visible alternation of differing images at rapidity which permits visual observation. I have found in practice that alternation of the images is best begun at the rate of about two occultations per second. and then gradually reduced to about one (or even less) per second. Sometimes it'is desirable to alternate as rapidly as two and. onehalf a second but if the speed is increased much above. this there is produced a mere blur or streak of light'which gives no information. The pur: pose of the occultation is qui y to show the ob.- server where differences in the two pages occur, and then to enable the observer to determine the nature of the differences. By observing all such flickers the places where differences occur in the twopages being collated are quickly found and noted;

In the accompanying drawings,

Fig, '1. is-a plan view of. a collation device which I have found suitable for this purpose.

ig. 2' is a side elevation of thesame.

Fig. 3 is an elevational view from the rear of the supporting mechanism upon which rests the projector i, Fig. 1, with capacity 'for linear adjustment.

Figs. 4 and 5 are respectively front and side views of one of the occulting discs; and

Figs. 6 and! are end and side elevational views of alternative mechanism which may be used to progress the microfilm when. held in a slide holder.

his a projector by which theimage of thepage of'a hook, or the, image of a reproduction (pref erably negatiye) of such page, is projected upon a. screen. "Thisprojected image falls first upon 5 and screw adjustments 5, 5, at its corners by.

means of which it is capable of very accurate positioning. A further adjustment is provided by mounting projector l upon its fixed support l5 with interposition of rails 16 mounted upon said support and also side guides H mounted upon the base of the projector so as to engage the opposing sides of the fixed support, thus insuring that motion upon the rails is in a true rectilinear direction. Such motion is accomplished by manipulation of the projector as by the handle i8. By this motion whenever it is found that the superimposed images diifer slightly in size as sometimes happens by reason oi paper shrinkage, or for other reasons, precise superimposition can yet be efiected.

T is an occulting disc mounted on a shaft 8 driven by the motor 9. Shaft a carries a bevel gear which gears with a similar gear on shaft ill upon which is mounted another occulting disc 1 i.

The occulting disc I is pla ced transversely to the path of the image from the projector '5, while the occulting disc ll is directly transverse to the path of the image from the projector i. Alternate occultation may be arranged by ny convenient shaping of the discs. I have found it convenient and suflicient to make each disc a half circle as shown in Fig. 2 at i l. The two half discs are arranged so that they occult alternately the images of which they cross the path, but any other convenient form of occultation may be used, and any rate of speed which is found effective may be used. The latter may be varied by rheostat l2 mounted on the table which carries the apparatus in order that the operator as he proceeds may control the operation, and control and change occulting speed as desired. This complete control of the speed of occultation is important. It is usually desirable to begin with about two or two and one-half occultations per second and then as flickers reveal the differences between the objects being compared gradually to reduce occultation speed so that the exact nature of the differences can be more closely observed.

For the purposes of insuring accurate superimposition of the images, it is important that the machine embody means by which occultation is at times prevented. For this reason occulting disc I I, as shown in Figs. 4 and 5, is mounted between smaller central rotating discs 20 and the occulting surface is divided into two quadrants 2| and 22, the latter fixedly mounted between central discs 20, while the other quadrant 21' is mounted upon a pivot 23 whereon it may be swung at times to a position corresponding with its fellow quadrant. In order to obtain superimposition of the two images the motion of the shafts of the occulting discs is stopped with disc 1 in its non-occulting position, and quadrants 2| and 22 are swung together into a position which allows the image from projector I to pass to the mirror without interference as the image from the other projector 4 is free to do, so that both images are simultaneously received upon the screen 3. After complete superimposition is satisfactorily obtained, quadrant H is swung to the position shown by the full lines of Fig. 4 whereupon rotation of the discs may be commenced with alternate occultation of the images for purposes of visual observation and examination of differences. It is also important that at times one or the other of the two images be maintained steadily upon the screen for examination and it is important that at all times the operator by ready manipulation may either effect superimposition of the two images, occultation of images in alternate succession, or the holding of one or the other image on the screen for a sufficient length of time for examination.

I have shown my apparatus in Figs. 1 and 2 as employing projectors of standard construction, and as fitted with microfilm roll-housings, i3, l3; but obviously any convenient form of projector may be used, and any convenient method of progressing film may be employed. For certain purposes it is preferable to use 35 mm. microfilm reproductions divided into sections and mounted upon a glass slide or between strips of glass which are capable of manual progression, manipulation and adjustment. In Figs. 6 and '7 I have shown such an arrangement. In Fig. 6, so and 3| are twin glass strips with a microfilm 32 between them forming a single slide. The slide and film are of a convenient length, say about twelve exposures. The slide thus produced is fitted into a holder 33 in the form of a frame of which 34 constitutes the bottom and 35 the top rail. The slide rests upon the bottom rail 34 being pressed in place by the springs 36. The holder is held in a frame 38 with aid of springs 39 and 40, and its horizontal position may be accurately adjusted by the adjusting screws H as is shown in Fig. 7. Although I have thus described an apparatus employing micro-film projectors, I

.- do not limit my invention to such as opaque-objects may be used.

The method of occultation may be varied by the use of any method by means of which the two superimposed images are rendered alternately visible. The use of the half-silvered mirror although' convenient is not the only means by which images from separate projectors may be superimposed with suflicient exactness and I therefore do not limit my invention to the particular pieces of mechanism which I have described. Moreover, since my invention may be used to facilitate'the collation of Various other kinds of graphic representations (as aforesaid; page 1 above), I do not limit my invention to a mechanism for the collation of books only.

I believe that I am the first who ever accomplished collation by the alternate occultation of superimposed projected images of the objects to be collated.

Having thus described my invention, I claim:

1. A collating device comprising a plurality of image projectors, a semi-transparent mirror pcsitioned for passage of the image projected from one of said projectors through it and for reflecting the image from a second projector along a path and on a projection surface whereby exact superimposition of one of said images upon the other is attained, movable occulting elements constructed and arranged for alternately occult ing the respective images, drive means for moving said occulting elements whereby said images are alternately viewable on said projection sur face, and means for positioning said occulting elements in non-occulting positions with respect to each projection path thereby providing simultaneous projection for superimposition, whereby diiferences between the two images may be made apparent.

2. A collating device comprising a plurality of image projectors, a semi-transparent mirror positioned for passage of the image projected from one of said projectors through it and for reflecting the image from a second projector along a path and on a projection surface whereby exact superimposition of one of said images upon the other is attained, movable occulting elements constructed and arranged for alternately occulting the respective images, drive means for moving said occulting elements whereby said images are alternately viewable on said projection surface, means for positioning said occulting elements in non-occulting positions with respect to each projection path, and control means constructed and arranged to vary the speed of said drive means and the occulting rate of said elements whereby differences between the two images may be made apparent.

3. The invention of claim 1 further characterized by the fact that said occulting elements comprise two half discs at least one of which is pivotally mounted for adjustment to a nonocculting position.

6 4. The invention of claim 2 further characterized by the fact that said drive means comprises an electric motor and said control means comprises a manually operable variable re- 5 sistance connected in circuit with said motor. CHARLTON HINMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 540,545 Gray June 4, 1895 1,506,524 Hammond Aug. 26, 1924 Re. 16,091 Marten June 2, 1925 1,899,032 Handschiegl Feb. 28, 1933 2,030,919 Harding Feb. 18, 1936 2,043,522 Valentin et a1. June 9, 1936 2,307,202 Eddy Jan. 5, 1943 2,365,613 Wibmer et a1. Dec. 19, 1944 2,406,451 Borkenstein Aug. 27, 1946 FOREIGN PATENTS Number Country Date 512,726 Great Britain Sept. 25, 1939 550,981 Great Britain Feb. 3, 1943 

